[swift-users] Type inference of array element type

[Mark Lacey]

> On Mar 24, 2017, at 3:08 AM, Toni Suter via swift-users <swift-users at swift.org> wrote:
> 
> Hi,
> 
> If I declare a variable and initialize it with an array literal whose elements are integer literals and nil literals,
> the compiler will infer the type Array<Optional<Int>> for that variable:
> 
> let arr = [1, nil, 3]
> print(type(of: arr)) 	// Array<Optional<Int>>
> 
> However, that only works with nominal types such as Int and String. If I do the same thing with an array of tuples,
> I get a compile error:
> 
> let arr = [(1, false), nil, (3, true)]		// error: type of expression is ambiguous without more context
> print(type(of: arr))
> 
> Why can't the compiler infer the type Array<Optional<(Int, Bool)>> in this example? Is there a reason for this or is it a bug?

Offhand it seems like we should be able to properly handle this. Can you open a bug report at bugs.swift.org <http://bugs.swift.org/>?

Mark

> 
> Thanks and best regards,
> Toni
> 
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